See also --transliterate-file-names, Since it came up: that feature is about (in practice) node names written in Cyrillic. It was originally proposed and implemented by Sergey to avoid having the HTML filenames be nothing but long __xx sequences.
http://www.gnu.org/software/texinfo/manual/texinfo/html_node/HTML-Xref-8_002dbit-Character-Expansion.html (I've fixed up the English there by now.) In any case, it has nothing to do with the case folding/preserving madness. k
